Periodontitis impacts as much as 47% of the U.S. population and is a significant cause for tooth loss in adults (Eke et al., 2010). Periodontitis is a chronic inflammatory lesion of the supporting structures of the teeth and is one of the most widely distributed and prevalent human diseases (Demmer et al., 2010; Cobb et al., 2009); this destructive process is driven by bacterial infections that colonize the tooth root surface (Darveau, 2010). Studies have demonstrated bacteremia and increased systemic inflammation appear to contribute to several diseases, such as cardiovascular disease, Alzheimer's disease, and diabetes (Offenbacher et al., 2009; Noble et al., 2009; Mealey et al., 2008). Studies have shown that there is a strong, bi-directional, relationship between diabetes and periodontal disease in which glycemic control is a major determinant (Mealey et al., 2008; Mealey et al., 2006; Lalla et al., 2006; Mealey et al., 2006; Campus et al., 2005; Tsai et al., 2002). However, additional pathways independent of glycemic control may exist that contribute to enhanced periodontal destruction in those with diabetes (Mealey et al., 2006). Type 1 diabetes (T1D) is an autoimmune disease resulting in the targeted destruction of pancreatic beta-cells and permanent loss of insulin production and is a leading cause of chronic disease in youth and young adults (Liese et al., 2010). Hyperglycemia is a classic manifestation of the disease (Atkinson et al., 1994; Mealey, 1999) and is a risk factor for complications such as atherosclerosis (Nathan et al., 2003). Hence, glycemic control is essential for disease management. Hemoglobin A1c (HbA1c), a measure of glycemic control, has been associated with increased levels of systemic inflammation (Kilpatrick et al, 2000; King et al., 2003), with concordant association with vascular complications of diabetes (Schram et al., 2005).
Saliva is an emerging and promising biofluid that has many advantages over serum, particularly the ease of collection and of storage (Chiappin et al., 2007; Lima et al., 2010). Most previous studies of biomarkers in diabetes have examined serum, however, serum is difficult and costly to obtain, and its large proteomic dynamic range has made novel biomarker analysis and subsequent interpretation confusing. Measurement of salivary biomarkers has been demonstrated in some populations, particularly for investigating periodontal disease (Giannobile et al., 2009; Gursoy et al., 2009; Gursoy et al., 2010), but little has been published on their presence in the saliva of Type 1 diabetics and their association with glycemic control.